Optical scanner apparatus with pinhole imaging device

ABSTRACT

A pinhole-imaging device used as an imaging device for an optical scanner apparatus. The pinhole-imaging device replaced the conventional lens-imaging device and placed in front of the optical sensor to receive the imaged light from the illuminant illuminated the scanning object and the optical imaging is focused on the optical sensor. When the radius of the aperture of pinhole-imaging device is smaller or equal to the pixel of the optical sensor, due to the imaged light transmitted to the aperture of the pinhole-imaging device to focus on the optical sensor to form an imaging such that the resolution of the optical imaging can be obtained and the light dispersion effect issue can be improved.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention generally relates to an optical scanner apparatus, and more particularly to an imaging device of an optical scanning module to prevent the light dispersion effect and obtain the better mtf (modulation transfer function).

[0003] 2. Description of the Prior Art

[0004] Scanner devices, such as flatbed scanners, are well known in the art and produce machine-readable image data signals that are representative of scanned object, such as a photograph or a page of printed text. In a typical scanner application, the image data signals produced by a scanner may be used by personal computer to reproduce an image of the scanned object in a suitable display device, such as a CRT (cathode ray tube) or a print.

[0005] Flatbed scanners are widely used with computer systems for converting printed data into image signals. An optical scanning module is the most important component of the flatbed scanner. The scanning module commonly comprises a housing with an opening for receiving light transmitted from a scanning object, an optical sensor such as CCD (charge coupled device) installed inside the housing for converting the transmitted light into corresponding image signals, and a plurality of lenses for focusing the transmitted light onto the optical sensor.

[0006] A typical flatbed scanner may include illumination and optical systems to accomplish scanning of the object. The illumination system illuminates a portion of the object (commonly referred to as a “scan region”), whereas the optical system collects light reflected by the illuminated scan region and focuses a small area of the illuminated scan region (commonly referred to as a “scan line”) onto the surface of a photosensitive detector positioned within the scanner. Image data representative of the entire object then may be obtained by sweeping the scan line across the entire object, usually by moving the illumination and optical systems with respect to the object.

[0007] The illumination system may include a light source (e.g., a fluorescent or incandescent lamp or an array if light emitting diodes (LEDs)). The optical system may include a lens and/or mirror assembly to focus the image of the illuminated scan line onto the surface of the detector. Alternative, a “contact image sensor” (CIS) may be used to collect and focus light from the illuminated scan region onto the detector.

[0008] The photosensitive detector used to detect the image light focused thereon by the optical system may be a charge-coupled device (CCD), although other devices may be used. A typical CCD may comprises an array of an individual cells or “pixels”, each of which collects or builds-up an electrical charge in response to exposure to light. Since the quantity of the accumulated electrical charge in any given cell or pixel is related to the intensity and duration of the light exposure, a CCD may be used to detect light and dark spots on an image focused thereon.

[0009] Referring to FIG. 1A, the reference number 100 is scanning g object; reference number 102 is reflected light which is illuminated the document to form a reflected light; reference number 104 is a conventional lens-imaging device of an optical scanning module; and reference number 106 is an optical sensor. In conventional scanning method of an optical scanner apparatus, a reflected light 102 from the scanning object 100 is transmitted to the lens-imaging device 104 to the optical sensor 106, and an optical imaging (not shown in FIG) is focused on the optical sensor 106. In the conventional optical scanning module, the imaging data is focused on the optical sensor 106 which is according to the theorem of the formation of image, the reflected light 102 is transmitted from the scanning object 100 to the lens-imaging device 104, the imaging data is communicated to the optical sensor 106. Then, the imaging data is treated and output to the output device, such as a print or monitor (not shown in FIG. 1).

[0010] The response distribution curve diagram of the FIG. 1B is formed that according to the FIG. 1A. According to the theorem of the formation of image, the reflected light point 102A, 102B, and 102C of the scanning object 100 and transmitted to the lens-imaging device 104 to the optical sensor 106 to form a response distribution curve diagram 200. Due to the light dispersion effect, the two ends 202A and 202B of the response distribution curve of the response distribution curve diagram 200 are lower than the response distribution curve that is formed from the light 102C (straight light) and other stream of light (not shown in FIG. 1B) between the ends 202A and 202B. Furthermore, due to the light dispersion effect, the imaging data cannot focus completely on a point such that the resolution of the imaging data on the two ends 202A and 202B is bad. Therefore, the resolution of the scanning object will be degraded.

[0011] In addition, the optical scanner apparatus with a lens-imaging device as a formation of image is used for scanning the scanning object 100, the optical image of the scanning object 100 is focused on the optical sensor 106 and converted the analogy signal into digital signal by ADC (analogy digital convert system). Therefore, in order to obtain a higher resolution, the number of pixel for CCD 106 must be increase.

[0012] However, the cost of the CCD 106 is proportional to the square of the number of pixels. When the higher resolution is required that will cause the cost of CCD 106 is a great part of the production of the optical scanner. Furthermore, the lens-imaging device exhibits a plane to scan the scanning object 100, and the MTF (modulation transfer function) is poor when the optical sensor 106 is diverged from the plane of the lens-imaging device 104.

SUMMARY OF THE INVENTION

[0013] It is an object of this invention to provide an imaging device to replace the conventional lens device to economize the cost.

[0014] It is a further object of this invention to provide an imaging device to improve the light dispersion effect.

[0015] It is yet object of this invention to increase the exposure to enhance the ratio of s/n (signal/noise).

[0016] According to abovementioned objects, the present invention provided an imaging device to replace the conventional lens-imaging device in an optical scanning module of an optical scanner apparatus. The imaging device such as a pinhole-imaging device is used to replace the conventional lens-imaging device in an optical scanning module to receive the illuminant, which is transmitted from the scanning object to the pinhole-imaging device and into the optical sensor such as CCD (charge coupled device) to form an optical imaging and focused on the CCD. The size of the aperture of the pinhole-imaging device can be equal or smaller than the pixel of the CCD such that the illuminant only illuminates through the apertures of the pinhole-imaging device to the CCD to reduce the light dispersion effect. Furthermore, in order to reduce the s/n (signal/noise) ratio, the scanning exposure is increased to obtain the better image qualities.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

[0018]FIG. 1A is a schematic representation showing the conventional optical scanner apparatus with lens-imaging device;

[0019]FIG. 1B is a schematic representation showing the response distribution curve diagram for an illuminant transmitted to the conventional lens-imaging device;

[0020]FIG. 2A is a schematic representation showing the macroscopic optical scanner apparatus with a pinhole-imaging device in accordance with a device disclosed herein;

[0021]FIG. 2B is a schematic representation showing the response distribution curve diagram for illuminant transmitted to the pinhole-imaging device in accordance with a device disclosed herein;

[0022]FIG. 3A is a macroscopic schematic representation showing the optical scanner apparatus with a pinhole-imaging device in accordance with a device disclosed herein; and

[0023]FIG. 3B is a schematic representation showing the signal profile for reflected light transmitted to the pinhole-imaging device in accordance with a device disclosed herein.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024] Some sample embodiments of the invention will now be described in greater detail. Nevertheless, it should be recognized that the present invention can be practiced in a wide range of other embodiments besides those explicitly described, and the scope of the present invention is expressly not limited except as specified in the accompanying claims.

[0025] Due to the conventional optical scanner apparatus with a lens-imaging device to scan the scanning object to form an optical imaging which is focused on the optical sensor. The conventional optical scanner apparatus with lens-imaging device for scanning object, due to the light dispersion effect such that the imaged light cannot focus completely on the optical sensor to cause the poor resolution when the imaged light is transmitted to the lens-imaging device to the optical sensor. Therefore, the present invention provided a pinhole-imaging device is used to replace the conventional lens-imaging device to improve the resolution of the optical imaging and light dispersion effect issue, and the MTF (modulation transfer function) also can be improved.

[0026] Referring to FIG. 2A, which is a macroscopic representation for an optical scanner apparatus with a pinhole-imaging device that according to the one embodiment of the present invention. The reference number 10 is a scanning object, number reference 12 is a imaged light, such as reflected light or transparent light, from the illuminant which is illuminated the scanning object 10, reference number 12A and 12B are represent the light point on the two end of the scanning object 10, and the reference number 14 is a pinhole-imaging device that is used to receive the imaged light 12 from the scanning object 10 and transmitted to the aperture 16 of the pinhole-imaging device 14 to the optical sensor 18, wherein the size of the aperture 16 of the pinhole-imaging device 14 is smaller or equal to the size of the pixel of the optical sensor 18 to focus the optical imaging on the optical sensor 18, herein, the optical sensor 18 can be a CCD (charge coupled device) or a CIS (contact image sensor), in the present invention, the optical sensor 18 is CCD.

[0027] Referring to FIG. 2B, which represents a response distribution curve diagram 20 that is formed from the imaged light 12 and transmitted to the aperture 16 of the pinhole-imaging device 14 to the CCD 18. Due to the imaged light 12 is transmitted to the aperture 16 of the pinhole-imaging device 14 and focused the optical imaging completely on the CCD 18 such that the light dispersion effect issue can be improved (FIG. 2B is compare with the FIG. 1B, the response distribution curve of FIG. 2B is superior to the FIG. 1B), therefore, the resolution can be enhanced when the imaging data is converted into the digital signal, and the quality of the optical imaging that is output to the monitor or printer also can be improved.

[0028] The FIG. 3A is an enlarged diagram for a pinhole-imaging device 16 to illustrate the imaged light 12 is transmitted to the pinhole-imaging device 14 to form an optical imaging on the CCD 18. In the one embodiment of the present invention, a scanning object 10 is illuminated by a stream of the light such that the scanning object 10 can be divided many sections, such as reference number 10A, 10B, and 10C (shown in FIG. 3). The stream of the light is illuminated each section 10A, 10B, and 10C and the imaged light 12 is transmitted from the scanning object 10 to the aperture 16 of the pinhole-imaging device 14 to the CCD 18. Then, the optical imaging is focused on the CCD 18. Similarly, the CCD 18 can be divided many sections, such as 18A, 18B, and 18C that are corresponding to the each section of the scanning object 10. The sections 18A, 18B, and 18C are showing that the imaged light 12 is transmitted from the scanning object 10 to the pinhole-imaging device 14, and the optical imaging is focused on the sections of the CCD 18. Due to the imaged light 12 is transmitted from the scanning object 10 to the pinhole-imaging device 14 such that the pinhole-imaging device 14 can focus the one of the optical imaging of the scanning object 10 completely on the CCD 18. According to aforementioned, each section of the scanning object 10 can be focused completely on the CCD 18 such that the resolution of the optical imaging can be improved, and the quality of the optical imaging also can be enhanced. Therefore, the light dispersion effect issue can be reduced and the MTF (modulation transfer function) can be improved.

[0029] Referring to FIG. 3B, the signal profile 30 is formed from the imaged light that is transmitted from the scanning object 10 to the pinhole-imaging device 16 and focused an optical imaging on the CCD 18. According to the signal profile 30, the each the pixel of the CCD 18 can receive the uniform illuminant from the stream of the light such that the each section can respond the uniform signal profile. Furthermore, the brightness of the illuminant is increased to increase the s/n (signal/noise) ratio, when the s/n ratio is increased the signal is greater than the noise such that the quality of scanning can be obtained and the MTF also can be improved. Moreover, the scanning exposure also can be increased such that the resolution of the optical imaging can be enhanced.

[0030] Then, the optical imaging is converted analogy signal into digital signal by ADC (analogy digital convert system) (not shown) and communicated to the ASIC (application specific integrated circuit). By use of the variety of chip set within the ASIC, the digital signal is communicated to the host (not shown) of a personal computer (not shown) by interface, wherein the interface can be a USB (universal serial bus), parallel port, SCSI TCP (small computer system interface transmission control protocol), or IR (infrared ray) communication. Next, the digital signal is communicated to the output device (not shown), such as monitor, printer, or PDA (personal digital assistant), to display the imaging data of the scanning object 10.

[0031] Although specific embodiments have been illustrated and described, it will be obvious to those skilled in the art that various modifications may be made without departing from what is intended to be limited solely by the appended claims. 

What is claimed is:
 1. An optical scanner apparatus, said optical scanner apparatus comprising: an illuminant illuminating a scanning object to form a imaged light from said scanning object, wherein said scanning object is positioned on a platen of said optical scanner apparatus; and a pinhole-imaging device receiving said imaged light and an optical imaging of said scanning object is focused on an optical sensor, wherein said optical sensor receiving said imaged light is communicated from said pinhole-imaging device.
 2. The optical scanner apparatus according to claim 1, wherein said pinhole-imaging device comprises an aperture.
 3. The optical scanner apparatus according to claim 2, wherein a radius of said aperture is smaller than a pixel of said optical sensor.
 4. The optical scanner apparatus according to claim 2, wherein a radius of said aperture is equal to a pixel of said optical sensor.
 5. The optical scanner apparatus according to claim 2, wherein said imaged light comprises a reflected light.
 6. The optical scanner apparatus according to claim 2, wherein said imaged light comprises a transparent light.
 7. The optical scanner apparatus according to claim 1, wherein said optical sensor is a charge coupled device.
 8. The optical scanner apparatus according to claim 1, further comprising an analogy-digital convert system receiving an imaging data that is communicated from said optical sensor and converting said imaging data into a digital signal.
 9. The optical scanner apparatus according to claim 1, further comprising an application specific integrated circuit receiving said digital signal that is communicated from said analogy-digital convert system and processing said digital signal.
 10. An optical scanner apparatus, said optical scanner apparatus comprising: an illuminant illuminating a scanning object to form a imaged light from said scanning object, wherein said scanning object is positioned on a platen of said optical scanner apparatus; a pinhole-imaging device with a aperture receiving said imaged light and focusing an optical imaging on a optical sensor, wherein said optical sensor receiving said imaged light is communicated from said pinhole-imaging device; an analogy-digital convert system receiving an imaging data that is communicated from said optical sensor and converting said imaging data into a digital signal; and an application specific integrated circuit receiving said digital signal that is communicated from said analogy-digital convert system and processing said digital signal.
 11. The optical scanner apparatus according to claim 10, wherein a radius of said aperture is smaller than a pixel of said optical sensor.
 12. The optical scanner apparatus according to claim 10, wherein a radius of said aperture is equal to a pixel of said optical sensor.
 13. The optical scanner apparatus according to claim 10, wherein said imaged light comprises a reflected light.
 14. The optical scanner apparatus according to claim 10, wherein said imaged light comprises a transparent light.
 15. The optical scanner apparatus according to claim 10, wherein said optical sensor is charge coupled device.
 16. An optical scanner apparatus with a pinhole-imaging device, said optical scanner apparatus comprising: an illuminant illuminating a scanning object to form a imaged light from said scanning object, wherein said scanning object is positioned on a platen of said optical scanner apparatus; a pinhole-imaging device with a aperture to receive said imaged light and focusing an optical imaging on a charge coupled device, wherein a radius of said aperture is equal to a pixel of said charge coupled device, wherein said charge coupled device receiving said imaged light is communicated from said pinhole-imaging device; an analogy-digital convert system receiving an imaging data that is communicated from said charge coupled device and converting said imaging data into a digital signal; and an application specific integrated circuit receiving said digital signal that is communicated from said analogy-digital converting system and processing said digital signal.
 17. The optical scanner apparatus according to claim 16, wherein said radius of said aperture is smaller than said pixel of said charge coupled device.
 18. The optical scanner apparatus according to claim 16, wherein said imaged light comprises a reflected light.
 19. The optical scanner apparatus according to claim 16, wherein said imaged light comprises a transparent light. 